SHUITOU, China — Along the valleys and mountains hugging the East China Sea, a Chinese government campaign to remove crosses from church spires has left the countryside looking as if a typhoon had raged down the coast, decapitating buildings at random.

In the town of Shuitou, workers used blowtorches to cut a 10-foot-high cross off the 120-foot steeple of the Salvation Church. It now lies in the churchyard, wrapped in a red shroud.

About 10 miles to the east, in Mabu township, riot police officers blocked parishioners from entering the grounds of the Dachang Church while workers erected scaffolding and sawed off the cross. In the nearby villages of Ximei, Aojiang, Shanmen and Tengqiao, crosses now lie toppled on rooftops or in yards, or buried like corpses.

On a four-day journey through this lush swath of China’s Zhejiang Province, I spoke with residents who described in new detail the breathtaking scale of an effort to remove Christianity’s most potent symbol from public view. Over the past two years, officials and residents said, the authorities have torn down crosses from 1,200 to 1,700 churches, sometimes after violent clashes with worshipers trying to stop them…

The campaign has been limited to Zhejiang Province, home to one of China’s largest and most vibrant Christian populations. But people familiar with the government’s deliberations say the removal of crosses here has set the stage for a new, nationwide effort to more strictly regulate spiritual life in China, reflecting the tighter control of society favored by President Xi Jinping.

In a major speech on religious policy last month, Mr. Xi urged the ruling Communist Party to “resolutely guard against overseas infiltrations via religious means,” and he warned that religions in China must “Sinicize,” or become Chinese. The instructions reflect the government’s longstanding fear that Christianity could undermine the party’s authority. Many human rights lawyers in China are Christians, and many dissidents have said they are influenced by the idea that rights are God-given.

…There are now about 60 million Christians in China. Many attend churches registered with the government, but at least half worship in unregistered churches, often with local authorities looking the other way.

But Mr. Xi’s decision to convene a “religious affairs work conference” last month — the first such leadership meeting in 15 years — suggested that he was unhappy with some of these policies. People familiar with the party’s discussions say it intends to apply some lessons from the campaign in Zhejiang to rein in religious groups across the country.

While the government is unlikely to begin tearing down crosses across China, the sources say, local authorities are expected to begin scrutinizing the finances and foreign ties of churches and other spiritual institutions as part of an effort to limit the influence of religions the party considers a threat, especially Christianity…

As the authorities pressed the campaign, prominent Protestant and Catholic leaders across China, including senior figures in the government’s religious affairs bureaucracy, spoke out against it in sermons and on social media.

One of them was Gu Yuese, the pastor of one of the biggest churches in the Chinese-speaking world, the Chongyi Church in the provincial capital of Hangzhou. As one of the best-known Protestant leaders in China, Mr. Gu was influential, and his criticism resonated beyond the region.

“These actions are a flagrant violation of the policy of religious freedom that the party and the government have been implementing and continuously perfecting for more than 60 years,” he wrote in a statement released on official government letterhead.

Then he was silenced. In January, the police detained Mr. Gu and charged him with misusing church funds [more here]. A few days later, another pastor in Zhejiang who had also spoken out was detained on similar charges…